For the past 10 years, the University of Tasmania sensor informatics professor and science leader at the CSIRO Computer Informatics Division has been working on the NASA Mars Exploration Rover mission.

He is the only Australian- based scientist working on the mission.

Most nights, when others are sleeping, Professor de Souza is telling the rovers where to move.

Mars was selected as a planet with potential life in 1969 when water channels were discovered by Mariner spacecraft.

"Where there is water, there is the potential to be life," Professor de Souza said.

In 1976, the Vikings satellites were sent to the red planet in search of water.

"But when they landed they just found desert," Professor de Souza said.

"There were no bushes, nothing, and, worse the rocks they found were primary rocks, which would dissolve quickly with the presence of water, so they wouldn't have seen water in their life."

In 1984, NASA found a tiny meteorite in Antarctica which had come from Mars.

"This meteorite was made of carbonate and carbonate needs water to be formed," Professor de Souza said.

"That discovery was so important as it was the most credible evidence we had of life beyond Earth."

So NASA started researching again with Mars Pathfinder, a microwave oven-size rover, which only found the same desert the Vikings satellite had.

However, NASA scientists were sure about the evidences of water.

"We just landed at the wrong place," Professor de Souza said.

New satellites were sent to Mars again to register detailed images of its surface and to select new places to explore.

Then on July 7, 2003, a rocket containing a rover called Spirit was launched to Mars.

It took three attempts for the rocket to be launched from Florida as no one could be near it.

"The distance we had to be was about the same as from Beauty Point to Launceston CBD," Professor de Souza said.

"We had to stop it one time because there were fishermen too close."

Seven months later, on January 3, 2004, Spirit landed on Mars.

But all scientists had discovered within a few weeks were the same rocks the Vikings and Pathfinder had in 1976 and 1997.

So another rover, called Opportunity, landed three weeks after and soon extended the initial three- month project to one about to celebrate its 10th anniversary.

"Opportunity landed in a small crater in an area about the same size of an auditorium," Professor de Souza said.

"We saw an interesting outcrop on the other side of the crater, so what we did, was go to that side and analyse it and what we found was a completely different situation.

"It was a rock made of two minerals, hematite and jarosite, that need water to be formed.

"We also found a lot of what we call blue berries, mineral spheres which are found in the bottom of the oceans on Earth."

That raised questions about whether there had been an ocean there.

The team found a bigger crater, called Victoria, where it discovered an eight-metre deposit of hematite and jarosite.

"That means we definitely had an ocean there for thousands of years," Professor de Souza said.

"What surprised us was this ocean was most likely to be very acidic [with a value worse than vinegar] because of rich sulphate and fluoride presence."

Meanwhile, Spirit found its first breakthrough: a rock made of amorphous silica like Australian opals.

The silica-rich deposits were evidence of a hot spring, like in Yellowstone National Park, in the US, or New Zealand's Rotorua.

"That was a huge discovery, because you'd have nutrients, energy, water, which is a perfect environment for life," Professor de Souza said.

"There is no hot spring on Earth where you won't find a lot of life, so that's probably a place we need to visit in the future and bring back some of these samples to Earth to study."

Spirit has since got stuck in the sand and is unable to move, but Opportunity is still roving its way around Mars exploring a 22-kilometre wide crater called Endeavour.

Professor de Souza still receives photos from Opportunity each day.

The equipment used for these rovers is one which is being used to analyse the environment in Tasmania by University of Tasmania students.

"We adapted one of the chemical analysers to one of the submarines from CSIRO and we determined areas where heavy metals are present in the Derwent estuary," Professor de Souza said.

"This is great for UTAS students as they have the chance to work with unique data from Mars."

He said with the Mars project he would like the Endeavour crater to be explored more to find out about the extent of the water.

Professor de Souza will continue to work for the rest of his life to find the answers and he believes in time, people will travel to Mars.

"But it will take them nine months to get there and they'll have to stay on the planet for a year," he said.